BY DR. R, VON LENDENFELD. 219 



I. FAMILY HYDKID^E. Huxley, 1856. 



Multiplying by budding or fission, and by sexual cells produced 

 in every Polype (1) Solitary. 



-SCHEMA. 

 Polype Ovum 



Polype 



I 

 Ovum. 



Protohydra. Greff. 



Hydra. Linne. 



Etc. 



2. FAMILY CLAYID^E. Yon Lendenfeld, 1884. non 

 Allman ! 



Forming colonies, all persons alike and all maturing (2) sexual 

 cells on hollow tentacular pi'ocesses. 



SCHEMA : 

 Ovum 



I 



Polype 



I 

 Hydrorhiza 



I 

 First Polype 



I 

 Ovum. 



(1.) In this and in other similar cases it is very likely, and has indeed 

 been observed, that although the Polypes which produce ova are similar to 

 others which may not appear adult ; budding and sexual propagation are 

 not carried on by the same individual at the same period. It appears 

 likely, that here, as in the Infusoria, periods of sexually multiplying and 

 budding generations alternate, and so a division of labour in time exists, 

 which may lead to a division of labour in space, if the budding persons 

 remain attached to one another. 



(2.) " Maturing " in this and the following definitions, because the 

 generative elements in many cases are produced elsewhere, and wander into 

 the place, where they finally reach maturity at a comparatively late period. 



